List of Known Codes
Content by Tomáš Slavotínek, Tim Clarke, and Christian PL.
IBM plant codes are 2-digit numbers identifying the facility where a given
product was manufactured and/or assembled. These codes can be found on many IBM
products - most significantly on assembled units and integrated circuits.
Systems and Other Units
Main units, monitors, terminals, storage units, and various other IBM
products typically come with a type/serial number sticker. The unique serial
number often starts with a 2-digit prefix - the plant code. Something like
Here the "55" indicates that the machine (IBM PS/2 Model 95) was
manufactured/assembled in Greenock, UK.
Similar information can be found on many IBM-made integrated circuits.
However, our understanding of the used format and values is very limited at the
moment. In general, the code consists of an "IBM" prefix, followed by one or
two 2-digit plant codes, terminated by an optional "Q", "P", or "PQ" suffix.
Here are a few examples:
IBM 53 52Q
IBM 93 14
The spacing between the individual sections seems to be greatly inconsistent
and most likely can be ignored.
The "IBM" prefix is self-explanatory. Sometimes it appears in form of the
striped IBM logo, but often shares a more pedestrian font with the rest of the
It's currently unknown what the "Q"/"PQ" suffix indicates. The most common
theory is that it stands for "Qualification" and "Pre-Qualification"
respectively. But if that's the case, then IBM shipped an awful amount of
pre-qualification IC samples in their products - which seems rather
questionable. The rare "P" suffix might stand for "Prototype" (seen on
THIS unreleased adapter).
Some chips have a single 2-digit plant number, while others have two 2-digit
numbers (4 digits total). The latter variant possibly indicates where the die
was fabricated and where the chip was packaged - in cases where the two aren't
the same (but it's unknown in what order, if correct at all).
List of Known Codes
Note: Some of the information presented here is
currently unconfirmed and may be inaccurate.
|02||Poughkeepsie, NY, USA|||
|10||Rochester, NY, USA|||
|11||Lexington, KY, USA|||
|26||Austin, TX, USA|||
|44||Santa Palomba, Italy|||
|55||Greenock, Scotland, UK|||
|65||Dublin, Ireland 93b|||
|72||Germany or USA?||units|
|83||Dublin, Ireland 99b|||
|694 (?)||United Kingdom|
-  IBM typewriter reference (thx Tim Clarke)
-  Empirical evidence (system units of known origins, etc.)
- Plant codes "53 14" and "93 14" appear on many PowerPC 601(+) CPUs. These
chips were produced only at Burlington, VT, USA and East Fishkill, NY, USA.
It's however unknown how this maps to the plant codes. The same code
combinations can be found on other (CMOS?) chips from the same era.